Ah... I was about to say the 330i/330ci factory brakes are actually very good but I'm guessing you've still got the small 318i brakes on your swapped 330i. Mind you its entirely possible I don't push them nearly as much, but bugger me if the stopping power of the 330ci hasn't saved me on a few occasions.
1998 328i Fern Green 5sp Steptronic - 270,000km
2000 330CI Sienna Red 5sp Manual - 130,000km